The objectives of this contract are to explore the following three approaches: Formation of a solid state dispersion or coprecipitate of the estrogen with various pharmacologically inert carrier substances., Formulation of lipid-in water emulsion dosage forms of the estrogen., Administration of the estrogen with certain competitive metabolic inhibitors in an attempt to reduce the extent of conjugation of the estrogen with glucuronic acid in the intestinal wall and/or during the first passage of the estrogen through the liver. These approaches will be evaluated pharmacokinetically using the dog as an animal model.